/**
 * Copyright (c) 2024 Hunan OpenValley Digital Industry Development Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include "GPUImageBrightnessFilter.h"

const std::string GPUImageBrightnessFilter::BRIGHTNESS_FRAGMENT_SHADER = R"(
    #extension GL_OES_EGL_image_external : require
    varying highp vec2 textureCoordinate;
    
    uniform samplerExternalOES inputImageTexture;
    uniform lowp float brightness;
    
    void main()
    {
        lowp vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);
        
        gl_FragColor = vec4((textureColor.rgb + vec3(brightness)), textureColor.w);
    }
)";

GPUImageBrightnessFilter::GPUImageBrightnessFilter() : brightness(0.0f) {}

GPUImageBrightnessFilter::GPUImageBrightnessFilter(const float brightnessValue)
    : GPUImageFilter(NO_FILTER_VERTEX_SHADER, BRIGHTNESS_FRAGMENT_SHADER)
{
    brightness = brightnessValue;
}

void GPUImageBrightnessFilter::onInit()
{
    GPUImageFilter::onInit();
    brightnessLocation = glGetUniformLocation(getProgram(), "brightness");
}

void GPUImageBrightnessFilter::onInitialized()
{
    GPUImageFilter::onInitialized();
    setBrightness(brightness);
}

void GPUImageBrightnessFilter::setBrightness(const float brightnessValue)
{
    brightness = brightnessValue;
    setFloat(brightnessLocation, brightness);
}